EP 942 061 A1 describes an electrochromic arrangement having a polymer electrolyte formed of a mixture of lithium conducting salts and preferably crosslinked polymers and aprotic solvents. It is mentioned therein that, when plastic substrates are used, it is desirable to provide a barrier layer to water in order to ensure reliable operation. A disadvantage is the multi-step nature of the application and the presence of counterions (chlorate, triflate, etc.), which is undesirable in particular applications.
WO 00/08523 A1 describes electrochromic arrangements in which the electrolyte layer is used as an adhesive layer. However, even this polymer electrolyte, consisting of lithium conducting salt, aprotic solvent and a crosslinked polymer matrix, cannot be applied from aqueous solution.
There is therefore a need for a simplified process for the production of electrochromic arrangements. There is also a need for a process that does not require the lithium conducting salts of the known electrochromic arrangements, as they are difficult to obtain commercially and, on account of their counterions (chlorate, hexafluorophosphate, triflate), are not ecologically harmless.
Furthermore, components that could be applied from water would be desirable for reasons of hygiene in the workplace, but this is impossible with the electrochromic arrangements known hitherto.
It would therefore be desirable to find an electrolyte that could be applied from water, that yields a stable electrochromic arrangement and that does not require separate lithium conducting salts.